Various types of ignitor devices have been devised in the past for the purpose of initiating combustion of fuel. Others have recognized the importance of transferring a large amount of energy from an energy source to a fuel air mixture in order to ignite the mixture and thus have resorted to incorporating capacitive elements in the ignitor for this purpose. Ignitor devices of the type described above may be more accurately characterized as conventional spark plugs which are concerned with producing a "hotter" spark. The peak power delivered to the electrical discharge of such devices is relatively low.
More recently, systems have been devised for increasing the efficiency with which electrical discharge energy is coupled to the fuel in order to initiate and promote a more rapid combustion event and extend the lean operating limit of the fuel mixture. For example, U.S. patent application Ser. No. 701,482, filed Feb. 14, 1985, discloses a system for initiating combustion of fuel, especially for internal combustion engines, which employs a very rapid, intense high power electrical breakdown to increase the rate of combustion and thereby reduce the need for advanced engine timing. The use of a driving circuit which has exceptionally low inductance and resistance results in the rapid electrical breakdown and coupling of at least 50 percent of the stored pulse energy to the breakdown channel within the first half period of the discharge current cycle. The resulting discharge effects enhance combustion of the fuel through, among other things, the cooperative effects of photolysis, supersonic hydrodynamic shock waves and high temperature thermal plasma. The ignitor device employed in the above-referenced system must possess extremely low inductance and resistance and may include means for storing a substantial amount of energy in close proximity to the electrodes of the device so as to quickly transfer this stored energy to the breakdown channel. The combustion ignitor of the present invention meets these requirements and is intended to be employed with such a system, although it is contemplated that the present invention could be used advantageously with other systems as well.